A new class of thermally and chemically stable donor-acceptor substituted thiophenes is presented. It is shown that exceptionally large electro-optic activity (as high as 30 pm/V at 1.3 micrometers ) can be achieved by doping/covalently bonding highly efficient trycyanovinylthiophenes into high temperature polymers such as polymidies and polyquinolines. Monitoring the long-term stability of electro-optic activity at temperatures above 100 degrees C has revealed that the covalent bonding approach is quite superior to the guest-host approach in polymide as well as polyquinoline based materials.